<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>日期</title>
</head>
<body>

</body>
<script>
    //时间
    var d = new Date()
    console.log(d.toLocaleString())

    //Math
    console.log(Math.PI)
    console.log(Math.ceil(3.14)) //向上取整 4
    console.log(Math.floor(3.14))  //向下取整 3
    console.log(Math.round(3.54)) //四舍五入
    console.log(Math.random()) //随机数 0-1之间的随机数
</script>
</html>